thanks for contacting HCM. dear patient usually the patients with hypertension or diabetes or both are the ones who usually have blocked coronary arteries and need bypass surgery. Hypertension does increase the risk in bypass surgery but even bigger risk is for diabetics who have greater risk and have delayed recovery from surgery. But most important is the center where you are undergoing surgery and the doctor and his track record. In general now a days bypass surgery is very safe and effective with very high survival rate and very high 25 to 30 years survival rate after surgery. So, just relax and get Bypass done at a good center. Best wishes for speedy recovery. Regards